This invention relates to an ultrasound system and method for versatile processing, such as compounding ultrasound data. In particular, both three and two dimensional representations are generated with reduced speckle, Doppler and B-mode two and three-dimensional representations are generated in various changeable combinations, versatile persistence processing is provided, and versatile image re-generation is provided.
Ultrasound data for various modes of operation are typically used to generate one or more images. Modes of operation include B-mode, color Doppler, Doppler Tissue Imaging(trademark) (see U.S. Re 35,720) and others. Conventional images include two and three-dimensional image representations.
As data is acquired, conventional systems mix different types of data to generate data for the image. For example, Doppler velocity data associated with Doppler energy data below a user or system set threshold is set to zero or assigned an appropriate color value. As another example, a plurality of frames of data are temporally persisted or filtered using an infinite impulse response filter. Typically, the mixing and other combination processing occurs as part of detection processing. The mixed data is then stored. The stored data is output and scan converted. The scan converted data is used to generate the image. However, to re-generate an image with different thresholds or other imaging parameters, data typically is re-acquired by scanning the patient.
There is growing interest in three-dimensional ultrasonic imaging, such as three dimensional ultrasound contrast agent imaging. To generate the three-dimensional image, volumetrically spaced information, such as planar or linear information, associated with positional information is obtained by using any of various transducers.
One approach is to use a two-dimensional transducer array to obtain three-dimensional image information directly. A two-dimensional array can be used to scan electronically in any desired orientation to acquire the desired information. Another approach is to collect multiple two-dimensional image data frames using a one-dimensional transducer array along with relative positional information among the image data frames so that these frames may be subsequently assembled in a three-dimensional volume to form the desired three-dimensional reconstruction.
Based on echo signals received from the transducer, the volumetric information, such as planar image information at a known orientation, is generated. The image information is derived as a function of various imaging modes. For example, B-mode or Color Doppler image information is generated. Once the volumetrically spaced information and associated positional information is provided, standard methods are employed for assembling the image information into a three-dimensional volume of the subject and for providing an appropriate display such as a cross section, a surface rendering, or the like.
For three-dimensional imaging, the scan converted data used to generate the image is output to a separate processor or computer. The computer arranges a plurality of sets of data representing two dimensions into a data set representing three-dimensions. A three-dimensional representation is then generated and displayed. Alternatively, a two-dimensional array is used to directly acquire a 3D data set. If the user desires to alter the image, such as by using a different threshold, new data is obtained by scanning the patient and arranged into a data set representing three-dimensions.
European Patent Application No. 0 797 106 A2 discloses an ultrasound system for three-dimensional imaging. B-mode and one type of Doppler data are stored and then mixed. The mixing is controlled by user entered opacities. However, the user control and mixing are limited.
For two-dimensional ultrasonic imaging, the two-dimensional or planar image information is used to generate a display. Typically, the planar information is obtained using a one-dimensional transducer array.
For both three and two dimensional imaging, speckle (a type of noise signal in coherent imaging) may reduce contrast resolution. U.S. Pat. No. 5,653,235 discloses a system for reducing speckle for two-dimensional imaging. A two-dimensional transducer array produces multiple beams at different orientations. See column 5, lines 5-46. The multiple beams are used to reduce speckle.
The present invention is defined by the following claims, and nothing in this section should be taken as a limitation on those claims. By way of introduction, the preferred embodiment described below includes a method and system for versatile processing of ultrasound data.
In a first aspect of the invention, a method and system for reducing speckle for three-dimensional images is provided. Various pluralities of two-dimensional frames of data spaced in elevation are compounded into one plurality of spaced two-dimensional frames of data. The frames of data are then used to derive a three dimensional set of data, such as by interpolation. Alternatively, the various pluralities of two-dimensional frames of data are used to derive the three-dimensional set of data. An anisotropic filter is applied to the set of data. The anisotropic filter filters at least along the elevation dimension. In either situation, various displays may be generated from the final three-dimensional set of data.
In a second aspect, a method and system for generating three-dimensional representations is provided. At least two sets of three-dimensional data corresponding respectively to two types of Doppler data are generated. The sets of data are then combined. An image or a quantity may be obtained from the combined data. By combining after generating the three-dimensional sets of data, the same, data (sets of data) may be combined a plurality of times pursuant to different relationships. Thus, a user may optimize the image or quantity.
In a third aspect, the two sets of three-dimensional data correspond to two types of B-mode, such as fundamental and harmonic frequency data. The combination is performed in response to user selection of the relationship between the sets of data.
In a fourth aspect, a three-dimensional representation is combined with a two-dimensional representation. The two images may be combined in user selected or system determined orientations. The combination may be altered or changed.
In a fifth aspect, two or three-dimensional sets of data are stored. A user may then select any one of various levels of persistence or filtering to combine the sets of data. The sets may represent the same or different regions of the patient. Since the sets of data are stored separately, the combination may be performed multiple times to identify diagnostic information.
In a other aspects, JPEG or other compressed data is combined, and an amount of combination in various embodiments is controlled as a function of a correlation between the sets of data.
In yet further aspects, ultrasound data is processed in response to one or more ultrasound image processes and corresponding parameters. The ultrasound data and the ultrasound image process parameters are stored or transmitted for re-generation of the same image in response to the ultrasound data and the previously used ultrasound image process parameters. The ultrasound system used to generate a first image, a remote ultrasound system or a remote workstation may be used to re-generate the same image.
Other embodiments are possible. Further aspects and advantages of the invention are discussed below in conjunction with the preferred embodiments.